<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>useFlex</title>
    <style type="text/css">
        body{

        }

        #roo {
            background-color: #aaaaaa;
            height: 200px;
            border: red 2px dashed;
            display: flex;
            width: 80%;
            justify-content: space-around;
        }

        .inn {
            margin: 5px;
            height: 100px;
            width: 150px;
            background-color: #007fff;
            text-align: center;
        }
    </style>
</head>
<body>
<div>
    <div id="roo">
        <span class="inn">1</span>
        <span class="inn">2</span>
        <span class="inn">3</span>
    </div>
</div>
</body>
</html>
